11 times / second times engine's capacity = a lot of exhaust gas.
11 * second * 1000cc /2
versus
3000 * second * 1000cc /2
The engine being a 4 stroke only admits air and fuel and only fires each cylinder on every second revolution.
Additionally, you need to take account of the throttle opening to calculate the exhaust gas volume because gas volume consumed and exhausted varies with throttle opening. At idle - very little gas is admitted to the cylinder whereas under various throttle openings, a very great deal more gas in and out is involved.
It is probably beyond amateur, back of the fag-packet calculation and needs a proper engineering evaluation, but we can certainly say that freewheeling down a long hill produces vastly less exhaust than driving down the same long hill.
Another way to compare the two conditions is to look at the fuel consumption since all exhaust is the result of burning fuel. The MPG figures shown on the computer really jump up when I operate it in that way. There is no doubt that less fuel is used, and less pollution is produced.
As for pollution - that only matters in a city centre. I avoid driving there like the plague. The car stays mostly in a rural location, covers 95% of its mileage in top gear on an A road or motorways, and never sits in urban traffic. Even when in the suburban location I avoid using it in busy times and only ever to get back out of the city.
The one way co2 emissions of that weekly trip involve 2.8 to 3 litres of petrol in 41 miles which equates to 13 to 14 kg of co2 emissions for the trip there and back. That is frankly little or nothing. A person just breathing, emits about a kilogram a day, so driving the car 82 miles a week is more or less twice what I breathe out in a week. Probably less actually, because i make sure to do some cardio type exercise every day, either spinning the ebike pedals or walking up hill out of breath. The standard estimate of a person breathing out 1kg of co2 per day assumes a pretty sedentary individual, and I am not that. I did 15400 steps yesterday.
EDIT:
Corrected car co2 emission.